James McClain Last year, prolific cult television show co-creator/writer/showrunner Josh Schwartz (“The O.C.,” “Gossip Girl,” “Chuck”) sold his longtime Los Feliz mansion to Ava DuVernay for nearly $10 million. But he isn’t downsizing — public records reveal the “Nancy Drew” helmer has just acquired an even larger compound in a leafy, affluent part of L.A.’s San Fernando Valley.The 2.3-acre, $8.1 million estate ranks as one of the largest properties in Sherman Oaks, per the listing.